(libobjc.a):  Compute srcdir1 without changing
	directories.  Use srcdir1 to locate objc/Makefile.  Put quotes
	around all potential multi-word values.  Recompute GCC_FOR_TARGET.
	(sublibobjc.a): Use same text as libobjc.a.
	(mostlyclean): Use $(MAKE) and srcdir1 for objc action.

From-SVN: r2491